The World Health Organisation says there is no licensed vaccine for the Ebola virus, but a promising candidate could be deployed within days

Geneva — An unlicensed Ebola vaccine could soon be tested in a remote region of the Democratic Republic of the Congo (DRC) hit by an outbreak of the virus, the World Health Organisation says.

There was no licensed vaccine for the Ebola virus, but a promising candidate vaccine could be deployed within a matter of days if the Congolese government gave its approval, the WHO said on Thursday.

"The preparations are in place. We could potentially mount a campaign within around a week, given all of the conditions … are met," WHO health emergencies chief Peter Salama told reporters.

Last week, the DRC declared an outbreak of the contagious disease, the eighth to date.

So far, two cases of the virus have been confirmed in a laboratory, while 18 others are suspected in the remote Bas-Uele province, an equatorial forest zone near the Central African Republic.

Three of those people have died. The first known case, a 39-year-old man, died on the way to hospital in Likati on April 22. A person caring for him and the motorcycle driver transporting him also died, Salama said.

This is the first outbreak of Ebola since the West Africa epidemic that ended in January 2016 after killing 11,300 people.

During that epidemic, a vaccine made by Merck was successfully tested in hard-hit Guinea. As in that test, the WHO would like to do a ring-trial in the DRC, meaning the vaccine would be given to all people who have had contact with known cases, as well as those who have had contact with them. Health workers would also be given the vaccine.

In addition to waiting for an official invitation from Kinshasa, there are a number of logistical challenges to rolling out a trial.

To start with, the vaccine needs to be stored at -80°C, which could be more than tricky in Likati, which is 1,300km from the capital.

"As you can imagine, in an area without telecommunications, without road access, without large-scale electrification, this is going to be an enormous challenge," Salama said.

But he said that huge efforts were under way to overcome the challenges.

The WHO emphasised its quick response since the DRC declared the latest outbreak on May 12. Airplanes and helicopters were being used to bring in health teams, which had already tracked down more than 400 people who had had contact with the known cases, Salama said.